Sony Betamax SL-100 - Noisy Output
 

Hey all. I have a Sony SL-100. The machine was playing "fine". I decided to give my machines a cleaning. After cleaning the head on this one the output was noisy as shown in the pictures. Gave the head another cleaning, but no help. I have used multiple tapes. Before I jump into this thing again, I was hoping someone may have some understanding of where this defect comes from so I can better focus my attention. Thank you for the input.

Video attachment
 

Here is a video file

That's all the symptoms of a dirty head or possibly a worn out one, but if it was fine before the cleaning, it makes me wonder if dirt was possibly introduced to the heads in some way.

Betamax has been my least favorite to work on in terms of getting tracking to work appropriately (I've gotten 3 out of 4 SL-HF900's going), but this doesn't really look like a tracking issue since the snow/comets are evenly distributed. I presume the noise doesn't change when you wiggle/rotate the output video connector at the player as it plays? No electrical interference that it could be picking up from nearby devices? This kind of looks like what you'd see back in the day when running a vacuum cleaner and watching over the air TV honestly.

But anyway, my guess is the cleaning process introduced dirt that wasn't originally in a place causing a problem, or there's the "stick-tion" (sticky friction) that can occur with betamax heads as the upper drum surface in particularly gets shiny from being polished by the tape going by. We kind of got lucky that VHS and spinning drums (rather than spinning head discs) were more prevalent and acted more like an air-bearing above the spinningdrum surface rather than betamax's dragging the tape across a long stationary surface as is it gets read.

Not that it matters, but betamax could have used an M-Loading style like VHS did. They actually made a betacam deck that does it decades later and they use the same form factor tapes as betamax: https://www.youtube.com/watch?v=EbUPfzZ1aEM&t=1370s


What was your cleaning process specifically? Is the top drum shiny at all? There's a process for de-shining it, but there's further risk to the alignment in my experience.

There is a common failure on beta machines of the head ground strap or brush, You may want to check that and clean it.

Thanks guys.

I clean it with lint free swaps, micro fiber rag and 99% alcohol.

I am going to open up and go back in.

What is the head brush. I will check it out and post a pic.

Thanks

Solved
 

Ok. I identified the issue. Never even opened it up. My capture computers are thinkpad w520s and I have each setup side by side by side. The power supply is for those model thinkpads are large. I had it sitting right beside the beta on the left side. Move the power supply or disconnect it from the laptop and it went away. The funny thing is, I have a Sony SL-25 Beta with the power supply in the same spot, but doesn't bother at all. Will keep those supplies away from my hardware going forward.

Thanks for the responses

Yes, all switched power supplies generate noise and must be kept from any analog signal transmission. The way they work by turning on and off the power in a duty cycle manner to curb the voltage creates a lot of sparking, This is why switched power supplies have higher caps failure compared to the old school bulky transformers.